High density polyethylene (HDPE)-based extrudable adhesives are of great interest because of their higher temperature resistance and better moisture barrier than those based on low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene-vinyl acetate (EVA), ethylene-methyl acrylate (EMA) or other ethylene copolymers. For some reason, which is not completely understood, the HDPE-based adhesives have poorer adhesion to polar polymers than those based on the other polyethylene polymers as described above.
In order to improve adhesion of the HDPE-based adhesives, elastomeric materials have been added to the composition. This solution is not always satisfactory since the elastomer usually lowers the softening point and MI considerably and also affects the stiffness and moisture barrier characteristics of the composition.